Different Interconnects for SOFC

2 Industrial processing technologies for the manufacture of metallic interconnects for SOFCs (Venskutonis and co-workers 2005) 

The glass seal must exhibit strong bonding at the interface to keep the residual stresses as low as possible. CTE mismatch between the glass and components of SOFC lead to thermal stress, which is given by the relation  

Such kind of reactions may lead to preferable gas leakage paths and hence affect the seal integrity. Severe interaction among the seal glass and the adjacent cell components increases the interfacial layer thickness, leading to the formation of pores and crack and at the interface and delamination of the glass. 

1 Alkali Metal-Based Glasses/Interconnects Interface 

Alkali metal glasses are successful in terms of thermomechanical performance, but possess severe corrosive action on the interconnects which puts a limitation on their applicability in a planar SOFC stack. The corrosion destabilises the protective chromia scale on the interconnect and hence affects the mechanical integrity of the stack. Nielsen and co-workers focused on the composite seals developed from the compliant glass (NAS—17.8 mol% sodium) dispersed with high CTE material such as MgO as MgO display slow crystallisation behaviour and desirable Tg values. Good adhesion between the NAS/MgO thin film composite glass composite with preoxidised Sandvik interconnect steel and (as received) Crofer 22APU is obtained at 950°C as shown in Fig. 6.3a, b. 

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